1. Field of the Invention
The present invention relates to a p-type semiconductor carbon nanotube, and more particularly, to a p-type carbon nanotube in which a halogen element is injected into a carbon nanotube to achieve hole-doping and a method of manufacturing the same.
2. Description of the Related Art
Carbon nanotubes were first discovered in 1991, and have been studied for use as micro electro mechanical system (MEMS) devices because of their good mechanical and chemical properties, their ability to have a very long cylindrical form with a diameter of several nanometers or tens of nanometers and a length of a micrometer and their good electrical conductivity. Studies for utilizing carbon nanotubes in various devices are being actively performed. Currently, carbon nanotubes are utilized in field emission devices, optical switches in the optical communication field, and in bio devices.
Carbon nanotubes are manufactured using arc discharge, laser deposition, chemical vapor deposition using a catalyst or screen printing, and methods for manufacturing carbon nanotubes are now well known.
Carbon nanotubes are p-type or n-type in order to be used as semiconductor devices such as complementary metal-oxide-semiconductor (CMOS) devices. It had been alleged that in most carbon nanotubes exposed to air, hole-doping (p-type doping) occurs due to the presence of oxygen, but it has been proven that oxygen in air does not cause hole-doping.
FIG. 1 is a cross-sectional view of an electronic device including n-type (electron-doped) carbon nanotubes disclosed in U.S. Pat. No. 6,723,624. To form the electronic device, a gate electrode 20 is formed on a substrate 10 and an oxide layer 11 is formed thereon. Thereafter, a first patterned metal layer 12 is formed on the oxide layer 11 and a carbon nanotube layer 13 is formed on the oxide layer 11 so as to correspond to the gate electrode 20. A gate layer 14 is then formed on the first metal layer 12 and the carbon nanotube layer 13. Such a method of manufacturing an n-type carbon nanotube is relatively well known.
A method of manufacturing a p-type carbon nanotube by depositing iodine or FeCl3, etc. on an outer wall of a conventional carbon nanotube is known. However, such a structure is unstable at high temperatures and leads to a change in the electron structure of the carbon nanotube. A method for manufacturing a stable p-type carbon nanotube is not yet known.